Diphosphorus Pentasulfide Composition for Stable Solid Electrolytes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The sulfide-based inorganic solid electrolyte material used in lithium ion batteries has lower lithium ionic conductivity compared to electrolytic solutions, necessitating an improvement while maintaining electrochemical stability.
Innovation Solution
A diphosphorus pentasulfide composition with a specific molar ratio of sulfur to phosphorus (S/P) and a DSC curve showing an endothermic peak in the temperature range of 280°C to 300°C with a half-width of 4.1°C or higher is used as a raw material to enhance lithium ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfide-based inorganic solid electrolyte material is used to replace electrolytic solution, then safety is improved and manufacturing cost is reduced, but lithium ionic conductivity deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the solid electrolyte material by controlling the molar ratio of Li2S to P2S5 within specific ranges (0.95≤Li2S/P2S5≤1.05 or 1.00≤Li2S/P2S5≤1.02) and adjusting the water content in raw materials to 10 ppm or less. These parameter optimizations enable the material to achieve both high safety and improved lithium ionic conductivity of 1.0×10^-3 S/cm or more at 25°C.
Solution Approach 2:
The patent creates a composite solid electrolyte material system combining Li2S and P2S5 in specific proportions, forming a composite material with optimized properties. This composite approach allows the material to maintain the safety advantages of solid electrolytes while achieving electrolyte-level ionic conductivity through synergistic composition design.
2Ease of manufacture
If conventional diphosphorus pentasulfide composition is used, then manufacturing is simplified, but lithium ionic conductivity deteriorates
Solution Approach 1:
The patent optimizes manufacturing parameters by specifying precise molar ratio ranges (0.95≤Li2S/P2S5≤1.05) and water content limits (10 ppm or less) for raw materials. These parameter specifications maintain manufacturing simplicity while dramatically improving lithium ionic conductivity to 1.0×10^-3 S/cm or more at 25°C, resolving the contradiction between ease of manufacture and performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed solution effectively improves the lithium ionic conductivity of the sulfide-based inorganic solid electrolyte material while maintaining electrochemical stability, enhancing the performance of lithium ion batteries.
Implementation Method 1
in a DSC curve of the diphosphorus pentasulfide composition obtained by measurement using a differential scanning calorimeter under conditions of a start temperature of 25° C., a measured temperature range of 30° C. to 350° C., a temperature increase rate of 5° C./min, and an argon atmosphere with a flow rate of 100 ml per minute, an endothermic peak is shown in a temperature range of 280° C. or higher and 300° C. or lower
Data Source
AI summary
Provided is a diphosphorus pentasulfide composition for a sulfide-based inorganic solid electrolyte material, in which a molar ratio (S/P) of a content of sulfur (S) to a content of phosphorus (P) is 2.40 or higher and 2.49 or lower. In the diphosphorus pentasulfide composition for a sulfide-based inorganic solid electrolyte material, in a DSC curve of the diphosphorus pentasulfide composition obtained by measurement using a differential scanning calorimeter under conditions of a start temperature of 25° C., a measured temperature range of 30° C. to 350° C., a temperature increase rate of 5° C./min, and an argon atmosphere with a flow rate of 100 ml per minute, an endothermic peak is shown in a temperature range of 280° C. or higher and 300° C. or lower, and a half-width of the endothermic peak is 4.1° C. or higher.